When vertebrate run, their legs showcase minimal contact with the ground. But insects are different. Such six-legged creatures run fastest using a three-legged or tripod gait where they have three legs on the ground at all times – two on one side of their body and one on the other. The tripod gait has long inspired engineers who design six-legged robots, but is it essential that the fastest and most effective method for bio-inspired robots to move on the ground?
Scientists at UNIL and EPFL disclosed that there is in fact a swifter method for robots to move on flat ground, provided they do not have the adhesive pads employed by insects to climb walls and ceilings. This suggests designers of insect-inspired robots must make a break with the tripod-gait paradigm instead consider other feasibilities comprising a novel locomotor strategy denoted as the ‘bipod’ gait.
The researchers carried out a range of computer simulations, tests on robots and studies on Drosophila melanogaster – the most popularly studied insect in biology. “We implied to identify why insects use a tripod gait and identify whether it is, indeed, the effective way for six-legged robots and animals to walk,” says Pavan Ramdya, co-author and corresponding author of the research.
To study the numerous combinations, the scientists employed an evolutionary like algorithm to optimize the walking speed of a simulated insect model based on Drosophila. Step-by-step, this algorithm sifted through numerous different possible gaits, eradicating the slowest and shortlisting the swiftest.
The scientists then created a six-legged robot efficient of using either the tripod or bipod gait. The bipod gait was again illustrated to be faster, correlating the simulation algorithm’s results. Ultimately, the studies examined the real insects. To see if leg adhesion might also play a major role in the walking coordination of real flies, they put polymer drops on the file’s legs to cover their claws and adhesive pads, as if the flies were wearing boots and watched what happened.
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